Step-by-step explanation: In order for a relation to be a function, a relation can not have the x-values repeat. Y-values can repeat an infinite amount of times but x-values can only repeat 1 time in a given relation. In relation A, you have (2,-2), and (2,3) and relation B, you have (9,3), and (9,-3). You can also graph both of these relations and do a vertical line test with your pencil and see that it would cross more than once.
A function is a relation that has a unique x value for every y value. This means that the x-values will never repeat. So, to figure out if a list of coordinates is a function check the x-values. If they never repeat, then it is a function. However, in the case of both A and B, the x-values repeat. For, relation A the value 2 repeats, and for relation B the 9 value repeats. Therefore, neither are functions.
